1. Field of the Invention
This disclosure relates to compounds and compositions suitable for use in surfactants. In particular, the disclosure relates to alkyl pyroglutamic acid compounds.
2. Description of Related Art
The large shift towards environmentally friendly surfactants has resulted in the need for the industry to provide readily biodegradable and non-toxic surfactants and additives. Surfactants and additives with renewable content can be preferable to their synthetic counterparts with demand being driven by life sustainability initiatives, preferred buying programs and consumer trends.
Alcohol ethoxy sulfates (AES) is a class of anionic surfactant commonly used in personal care shampoo formulation. The trace byproduct from the manufacturing processes of AES (alkoxylation and sulfation), and the skin irritancy associated with AES are not desirable in personal care applications. An ethylene oxide-free (EO-free) and sulfate-free surfactant that is non-irritating is much more preferable in personal care.
Common EO-free and sulfate-free surfactant personal care surfactants are fatty acid soaps, betaines, alpha olefin sulfonates, sulfosuccinates, esters, alkyl polyglucosides, fatty acyl amino acids, fatty amine oxides, and quaternaries. Two common commercially available amino acid surfactants are acyl glutamate and acyl sarcosinate. Acyl glutamate is derived from natural fatty acids and natural glutamic acid, while acyl sarcosinate is derived from natural fatty acids and synthetic glycine. In either case, these amino acid surfactants are commonly accepted as non-toxic and mild. They are used mainly in personal care applications, but not as widely used as alkyl polyglucosides (APG) due, at least in part, to the use of fatty acid chlorides as intermediates in amide formation with the amino acid of choice.
The preparation and use of corrosive acid chlorides imparts cost to the amide-based amino acid surfactants and generation of a full equivalent of waste from the chlorinating reagent. Additionally, the isolation of the desired fatty acid amide from salt byproduct and water also adds cost relative to other surfactants.